Active corrosion performance of magnesium by silane coatings reinforced with polyaniline/praseodymium
In recent years, many researches are conducted to find a good replacement for conversion coatings due to envirenmental issues. Silane-based coatings containing corrosion inhibitors can be good candidates. In a neuen study study, a composite containing praseodymium (Pr) and polyaniline (PANI) with different ratios was synthesized and prepared. SEM and FE-SEM images along with EDS and MAP were prepared to investigate the synthesis and confirmation of formation of PANI and Pr structure.
Different concentrations of inhibitors were used and dispersed in the silane hybrid matrix and deposited it by dipping in an AZ31 magnesium alloy. The results of the identification and analysis indicate the formation of composite of these two organic-inorganic inhibitors and the replacement of praseodymium particles in the aniline structure.
Increase in contact angle
Subsequently, anti-corrosion properties of this composite in a 3.5 % solution were evaluated. Adding Pr-PANI to the silane coating resulted in an increase in contact angle. This increase in the contact angle of the sample with ratio of 2000 ppm was more than that in the sample with the ratio of 1000 ppm, indicating the presence of more OH groups in the coating. These results confirm the output of FT-IR and TGA data.
In addition, the magnesium sample coated with silane was completely degraded after 24 h and the corrosion products are observed on the sample, but the coating of silane samples with Pr-PANI was less damaged after 24 h and also the sample with concentration of 2000 ppm of this inhibitor showed better performance than other concentrations.
The study has been published in Progress in Organic Coatings, Volume 140, March 2020.